MUNISI DISSERTATION REPORT FINAL[1].pdf - muhas

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2.1.3. Relationship between STH infections and anthropometric indices of school
children
Soil-transmitted helminths infections rarely cause death. Instead, the burden of disease is
related less to mortality than to the chronic and insidious effects on the hosts’ health and
nutritional status (Stephenson et al., 2000). Chronic STH infections resulting from Ascaris
lumbricoides, Trichuris trichiura, and hookworm can dramatically affect physical and mental
development in children (WHO, 2002). There is now a substantial body of research that
clearly demonstrates how STH infections impair healthy nutrition (Stephenson et al., 2000).
STH impair the nutritional status of the individuals they are infecting in multiple ways, by:
Feeding on host tissues, including blood, which leads to a loss of iron and protein;
Malabsorption of nutrients;
Competing for vitamin A in the intestine in particular roundworm;
Causing inflammatory responses that may affect appetite and food intake, or
substances that modify the metabolism and storage of key nutrients such as iron
(WHO, 2012).
The three most frequently used indicators of nutritional status of children i.e. height-for-age,
weight-for-age and weight-for-height are based on weight and height measurement (FAO,
2012). Based on these, a child is considered stunted if the child is too short for his/her age.
Stunting reflects failure to receive adequate nutrition over a long period of time and is affected
by recurrent and chronic illness. Height-for-age, therefore, represents the long-term effects of
malnutrition in a population and is not sensitive to recent, short term changes in dietary intake
(National Bureau of Statistics, 2010). The weight-for-height data assesses whether or not the
child is wasted. A child is considered wasted if the child is too thin, that is, weighs too little
for his/her height. Wasting is an indicator of acute or recent nutritional deficits and is closely
tied to mortality risk. The weight-for height indicator also can be used to assess the extent to
which children are overweight or obese, which is an increasing problem among children
worldwide. Finally, the weight-for-age indicator provides an assessment of whether a child
weighs too little for his/her age. A child can be underweight for his/her age because the child